
Trichobothria (singular trichobothrium) are elongate
setae ("hairs") present in
arachnids, various orders of
insect
Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...
s, and
myriapods that function in the detection of airborne vibrations and currents, and electrical charge. In 1883,
Friedrich Dahl observed that they were deflected by the sound waves from a violin and labelled them 'hearing hairs'.
Morphology
Unlike the ordinary setae, which are tapered, the trichobothria have the same gauge throughout their length. They fit into the bottom of a broad and deep cup to which connects a membrane with extreme flexibility which adds an extraordinary mobility to them. The least air vibration is able to get them moving and to excite the small group of sensory cells which ensures their innervation.
Distribution
Trichobothria are present in most orders of the
Arachnida, except in
Solifugae
Solifugae is an Order (biology), order of Arachnid, arachnids known variously as solifuges, sun spiders, camel spiders, and wind scorpions. The order includes more than 1,000 described species in about 147 genus, genera. Despite the common names, ...
,
Ricinulei and
Opiliones
The Opiliones (formerly Phalangida) are an Order (biology), order of arachnids,
Common name, colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs (see below). , over 6,650 species of harvestmen have been discovered w ...
(Grassé, 1949). Although the distribution of trichobothria on the bodies of
arachnids is often used by systematists
(especially in
Scorpiones and
Pseudoscorpiones), few interordinal patterns are apparent (Shultz, 1990).
References
* Foelix, R.F., 1982. Biology of Spiders. Harvard University Press. Cambridge, Massachusetts, and London, England.
* Grassé, P. (1949). Traité de Zoologie: Anatomie, Systématique, Biologie / publié sous la dir. de M. Pierre-P. Grassé. tome VI, Onychophores - Tardigrades - Arthropodes - Trilobitomorphes - Chélicérates. - Masson et Cie, Paris.
* Shultz, J.W. (1990). Evolutionary Morphology And Phylogeny of Arachnida. Cladistics 6: 1-38.
Arachnid anatomy
Arthropod anatomy
Insect anatomy
Animal hair
Sensory organs in animals
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